Ultrahigh molecular weight polyethylene (UHMW-PE) is a kind of thermoplastic engineering plastic with linear structure and excellent comprehensive properties.
Before the 1980s, the world’s average annual growth rate was 8.5%. After the 1980s, the growth rate reached 15% ~ 20%. The average annual growth rate in China is above 30%. In 1978, the world consumption was 12,000 ~ 12,500 tons, and in 1990, the world demand was about 50,000 tons, of which the United States accounted for 70%. From 2007 to 2009, China gradually became the world’s engineering plastics factory, and the ultra-molecular weight polyethylene industry developed very rapidly. The development history is as follows:
The basic theory of ultrahigh molecular weight polyethylene fiber was first proposed in the 1930s.
The emergence of gel spinning and plasticized spinning has made great breakthroughs in the technology of ultra-high molecular weight polyethylene.
In the 1970s, Capaccio and Ward of the University of Leeds in the United Kingdom first developed high molecular weight polyethylene fiber with a molecular weight of 100,000.
In 1964, it was successfully developed and put into industrial production in China.
In 1975, the Netherlands invented Gelspinning using decalin as solvent, successfully prepared UHMWPE fiber, and applied for a patent in 1979. After ten years of research, it is proved that the gel spinning method is an effective method for producing high strength polyethylene fiber, which has a promising industrial future.
In 1983, ultra-high molecular weight polyethylene (UHMWPE) fiber was produced in Japan by gel extrusion and super stretching method with paraffin as solvent.
In China, ultra high molecular weight polyethylene pipe was listed as the key promotion plan of national scientific and technological achievements in 2001 by the Ministry of Science and Technology (2000)056 document, which belongs to new chemical materials and new products. The Ministry of Science and Technology of the State Planning Commission has listed ultra-high molecular weight polyethylene pipe as a priority project in the key field of high-tech industry.
Identify methods
Ultra-high molecular weight polyethylene is a kind of polymer compound, it is difficult to process, and has super wear resistance, self-lubricating, high strength, stable chemical properties, strong anti-aging performance, so in the discrimination of true and false polymer polyethylene, we must pay attention to the characteristics of it, the specific discrimination method is as follows:
1. Weighing rule: the proportion of products made of pure ultra-high molecular weight polyethylene is between 0.93 and 0.95, the density is small, and it can float on the water surface. If it’s not pure polyethylene, it will sink to the bottom.
2. Visual method: the surface of real ultra-high molecular weight polyethylene is flat, uniform, smooth and the density of the section is very uniform, if it is not pure polyethylene material color is dim and the density is not uniform.
3 edge test method: pure ultra-high molecular weight polyethylene flanging end face is round, uniform, smooth, if not pure polyethylene material flanging end face crack, and after heating flanging will appear slag phenomenon.